That there is a heritable or familial component of susceptibility to chronic non‐communicable diseases such as type 2 diabetes, obesity and cardiovascular disease is well established, but there is increasing evidence that some elements of such heritability are transmitted non‐genomically and that the processes whereby environmental influences act during early development to shape disease risk in later life can have effects beyond a single generation. Such heritability may operate through epigenetic mechanisms involving regulation of either imprinted or non‐imprinted genes but also through broader mechanisms related to parental physiology or behaviour. We review evidence and potential mechanisms for non‐genomic transgenerational inheritance of ‘lifestyle’ disease and propose that the ‘developmental origins of disease’ phenomenon is a maladaptive consequence of an ancestral mechanism of developmental plasticity that may have had adaptive value in the evolution of generalist species such as Homo sapiens. BioEssays 29: 145–154, 2007. © 2007 Wiley Periodicals, Inc.